10.4 usable nights
8–13 in the middle half of years · 3.5 typically near a dark moon.
335 astronomical-dark hours in an average month
20-year trip-planning baseline
Best time to stargaze at Eagle Pass
October: 17.4 usable nights on average. Use this seasonal climate baseline to choose a month, then use the live forecast to choose a night.
Site darkness · modelled, not measured
Bright skyBortle classes describe observed sky conditions; this brightness model does not establish a measured Bortle class.19.3–20.0 mag/arcsec²
The short answer
October has been strongest.
It averages 17.4 usable nights, versus 8.2 in May. A typical October lands between 14 and 23 usable nights.
Record2005–2024 · 20 complete years
Usable nightAt least 3 astronomical-dark hours and NASA POWER nighttime cloud ≤30%
Dark-moon nightUsable night with ≤25% illumination at local solar midnight
ResolutionCERES SYN1deg 1° cloud grid; regional climate, not a campsite guarantee
Seasonal fingerprint
Usable nights by month
Month by month
8.3 usable nights
6–11 in the middle half of years · 2.3 typically near a dark moon.
283 astronomical-dark hours in an average month
9.4 usable nights
7–12 in the middle half of years · 3.2 typically near a dark moon.
297 astronomical-dark hours in an average month
8.6 usable nights
6–10 in the middle half of years · 3.6 typically near a dark moon.
241 astronomical-dark hours in an average month
8.2 usable nights
4–12 in the middle half of years · 2.4 typically near a dark moon.
248 astronomical-dark hours in an average month
11.2 usable nights
9–14 in the middle half of years · 2.9 typically near a dark moon.
192 astronomical-dark hours in an average month
11.4 usable nights
7–14 in the middle half of years · 4.5 typically near a dark moon.
230 astronomical-dark hours in an average month
13.8 usable nights
12–17 in the middle half of years · 4.4 typically near a dark moon.
248 astronomical-dark hours in an average month
14.3 usable nights
11–18 in the middle half of years · 5.1 typically near a dark moon.
268 astronomical-dark hours in an average month
17.4 usable nights
14–23 in the middle half of years · 6.2 typically near a dark moon.
310 astronomical-dark hours in an average month
12.4 usable nights
8–17 in the middle half of years · 4.0 typically near a dark moon.
320 astronomical-dark hours in an average month
10.0 usable nights
6–13 in the middle half of years · 3.3 typically near a dark moon.
324 astronomical-dark hours in an average month
Use the baseline honestly
Climate chooses the month. Forecasts choose the night.
The cloud product is a roughly 1° regional grid. It can reveal seasonality, but it cannot know a mountain ridge, valley fog pocket, locked gate, smoke event or the exact sky you will get.
Source: NASA POWER daily data, parameter CLOUD_AMT_NIGHT from the CERES SYN1deg cloud product. GoodSeeing calculates astronomical darkness and lunar illumination independently for each place.